Process of treating wood for the production of paper-pulp, terpenes, and resinous substances.



PATENT GEoEGE P. GEAIGHILL AND GEORGE A. KERR, OF LYNOHBURG, VIRGINIA ASSIGNORS TO N. C. MANSON, JR, OF LYNCHBURG, VIRGINIA.

PROCESS OF TREATING WOOD FOR THE PRODUCTION OF PAPER-PULP, TERPENES, AND RESINOUS SUBSTANCES.

Specification of Letters Patent. Application filed December 28, 1904. Serial No. 238,627.

Patented April 1'7, 1906.

T (ZZZ whomit may concern.-

Be it known that we, GEORGE P. CRAIG- HILL and GEORGE A. KERR, of Lynchburg,

in the county of Campbell and State ofVirginia, have invented certain new and useful Improvements in Processes of Treating Wood foi the Production of Paper-Pulp, Terpenes, and Resinous Substances; and we do hereby declare the followin to be a full, clear, and exact description 0 the invention, such as will enable others skilled in the. art to which it appertains to make and use the same.

The object of this invention is to produce white paper pulp from resinous or fatty woods by a process which insures the removal and recovery of the volatile substances and resinous matter at a preliminary stage that is to say, before the reduction of the wood to a pulp.

A further object is to efiect the removal of all coloringmatter from the resinous or fatty iggod by digestion without. injury to the er. a The invention will now be fully set forth, and particularly pointed out in the claims.

The wood after being reduced to chips or shavings is placed in a suitable digester, whereinit is saturated with just enough alka line solution, preferably caustic soda, to have the effect of artially dissolving the resinous contents of t e wood and of opening up the cells thereof, so that upon the ap lication of heat the terpenes are liberated, t e solution also serving to fix the various volatile acids and oils and prevent their passing off with the terpenes. The strength of this first solution varies with the proportion ;of rosin contained in, the wood undergoing treatment, but is always just sufficient to saponify the rosin and oils and neutralize the acids without dissolving the other extractive matters of the wood. The digester being closed, steam or a current of heated air, or a mixture of both, is then applied to the mass. The terpenes are carried off through a suitable openin in the topof the digester and are recovere at will by the ordinary methods of condensation. The volatile acids, however, are neutralized by combination with the soda and do not pass off with the terpenes. Al'- though the rosin is partially saponified, it is, not completelyso at this stage of the process.

' The distillation being completed, a sufficient quantity of water is added to submerge the wood, steam isapplied, and the wood is digested at a temperature equal to the boilingpoint of the alkaline solution with which the mass was saturated and the digestion continued until the rosin has completely entered "into combination by saponification with the alkaline solution. Thereupon the solution is drawn off and the wood well drained. It is tobe noted that before reducing the wood to pulp the volatile substances and resinous matter are separately removedand recovered.

The solution, containing the rosin, oils, and some acid, being drawn off, as stated, the digester is a ain charged with a solution of caustic soda rom 1.075 to 1.10 specific gravity, and the digestion of the wood is continued under pressure until it is reduced to ultimate fiber; Inasmuch as it is difficult if not impossible to remove all the coloring-matter from resinous or fatty woods by digestion with caustic soda without great injury to and loss of the fiber, we then draw off this second soluwith a solution of carbonate of soda, in the ing the digestion is continued. This serves to remove the yellow coloring-matter without injury to the fiber and leaves the latter in such condition that it can be readily whitened or bleached. The carbonate of soda leaves the fiber about the color of light Manila wrappingpaper, rendering but little bleaching necessary to make the pulp applicable for use in the manufacture of white paper.

By using a solution of caustic soda of the specific gravity-named we avoid the loss and injury of the fiber incident to the use of stronger solutions. Strong caustic-soda solutions not only have the effect of dissolving part of the fiber, but of also injuring the quality of that which remains by making it brittle. It is not essential that the treatment of the pulp with carbonate of soda should be under pressure, as the same effect can be obtained by boiling the pulp in the solution. As a matter of convenience and economy we have found it desirable to use the carbonateof-soda solution under pressure before removing the pulp from the digester. The pulp is then bleached with chlorm or any of the acid tion of caustic soda and charge the digester presence of which under pressure or by boilbleaching reagents. We have found that the most effective method of bleaching is by the use of chlorinated soda containing from .05 percent. to .1 per cent. chlorin.

The advantages of our invention will be at once apparent. It will be seen that in preparing the wood for digestion we not only remove all volatile substances and resinous matter, but are enabled to recover the same, the terpenes alone-being of great val'v e, sinceby the described process they are carried off in a pure and colorless state. It follows that the volatile substances and resinous matter being removed before digestion takes place the wood is more easily reduced to ultimate fiber and requires but little treatment before it can be used as paper-pulp. It will also be seen that by subjecting the Wood fiber to the solution of carbonate of soda followin the action of the solution of caustic soda al yellow coloring-matter'is removed. In consequence but little bleaching is then required, and this is most effectively secured by the application of chlorinated soda.

We claim as our invention- 1. The herein-described method of producing paper-pulp from wood and extracting and recovering volatile and resinous constituents of the wood, which consists, first, in chemic ally treating the wood just enough to fix the volatile acids and oils and liberate the terpenes, second, subjecting the mass to the action of heat to volatilize and carry off the ter penes in apure and colorless state, third,with drawin the resinous substances. including the aci s and oils, and then chemically treating the residual fibrous constituents of the wood to reduce them to fiber and remove coloring-matter therefrom. 2. The herein-described method of producing paper-pulp from wood and extracting and recovering volatile and resinous constituents of the wood, which consists, first, in chemicallytreatin the wood just enough to fix the v0 atile acic is and oils and liberate the terpenes, second, subjecting the mass to the action of heat to volatilize and carry off the terpenes in'a pure and colorless state, and third, I withdrawing the resinous substances including the acids and oils, then chemically treating the wood under pressure, to reduce it to,

fiber. I v

3. The herein-described method of producrecovering volatile and resinous constituents of the wood, which consists,first, in chemically treating the wood to fix the volatile acids and oils and liberate the terpenes, second, subjecting the mass to the action of heat to volatilize and carry off the terpenes in a pure and colorless state, third, Withdrawing the resinous substances including the acids and oils, then chemically treating the wood under pressure, to reduce it to fiber, then further chemically treating it to remove the remainbleaching the pulp.

4. The herein-described method of produc ing paper-pulp from wood and extracting and recoveirng volatile and resinous constituents of the wood, which consists, first, in chemicallytreating the wood to fix the volatile acids arid oils and liberate the terpenes, second, subjecting the mass to the action of heat to volatilize and carry off theterpenes in a pure and colorless state, third, withdrawing the resinous substances inclttdin the acids and oils, thend'urther digesting t e wood to re duce it to fiber and removec'oloring-matter by subjecting it,first, to a solution 0? caustic soda, under ress'ure, and, secondly, to a so lution of car onate of soda.

5. 'The herein-described method of producing paper-pulp from wood and extracting and recovering volatile and resinous constituents of the wood, which consists, first, in chemically treating the Wood under moderate heat to liberate the terpenes and fix the volatile acids and oils, the terpenes being carried on" and recovered, then further digesting the wood at a moderate temperature in the same chemical solution, then drawing off the solution and resinous substances, then subjecting the residual fibrous constituents to a solution of caustic soda, under pressure, and then to a solution of carbonate of soda, and then bleac ing by the action of chlorinated soda.

specification in the ing witnesses.

GEORGE A. KERR.

Witnesses:

J. D. O EN, .H. E. ORCHARD...

5 ing portions of coloring-matter, and then" cEo. P. o'RAIeHiLL. 

